Rigging issue - The bottom of the torso is moving, where I only want the top to for this bone
Select the center edge loop in weigh paint mode (use vert mode button in top panel to be able to do that or do it edit mode by going to the vertex group panel and remove the vertex from the vertex group) and set the weight to 0 in the weight slider, and press Shift+K to assign weights (but in this case removing)...